LOCATION BOMBADIL NV+CA

Established Series
Rev. EWB-JBF-TM-JVC
11/2016

BOMBADIL SERIES

The Bombadil series consists of very shallow and shallow, well drained soils that formed in colluvium and residuum derived from volcanic rocks. Bombadil soils are on hills, plateaus, and mountains. Slopes are 2 to 50 percent. The mean annual precipitation is about 250 mm and the mean annual temperature is about 8 degrees C.

TAXONOMIC CLASS: Loamy, mixed, superactive, mesic Lithic Xeric Haplargids

TYPICAL PEDON: Bombadil stony fine sandy loam--rangeland. (Colors are for dry soil unless otherwise noted.) The surface is covered by approximately 20 percent gravel, 10 percent cobbles, and 7 percent stones.

A--0 to 5 cm; light brownish gray (10YR 6/2) stony fine sandy loam, brown (10YR 4/3) moist; moderate thin platy structure; soft, very friable, slightly sticky and slightly plastic; very few fine roots; many fine vesicular pores; 5 percent stones, 5 percent cobbles, and 10 percent gravel; slightly alkaline (pH 7.4); clear smooth boundary. (3 to 13 cm thick)

Bt1--5 to 15 cm; brown (10YR 5/3) loam, brown (10YR 4/3) moist; weak coarse prismatic structure parting to weak fine subangular blocky; slightly hard, very friable, slightly sticky and slightly plastic; many very fine, fine, medium and coarse roots; many very fine interstitial, and many very fine, fine and medium tubular pores; common faint and few distinct clay films on faces of peds and lining pores; 10 percent gravel; neutral (pH 7.2); clear wavy boundary. (5 to 15 cm thick)

Bt2--15 to 25 cm; pale brown (10YR 6/3) clay loam, brown (10YR 4/3) moist; weak coarse prismatic structure parting to weak fine subangular blocky; slightly hard, very friable, moderately sticky and moderately plastic; many very fine, fine, medium, and coarse roots; many very fine interstitial and many very fine, fine, and medium tubular pores; common faint and few distinct clay films on faces of peds and lining pores; 10 percent gravel; neutral (pH 7.2); abrupt wavy boundary. (10 to 15 cm thick)

R--25 cm; basalt; highly fractured in the upper 10 cm with common very fine and fine roots, fine-earth, and discontinuous silica and secondary carbonates lining fractures.

TYPE LOCATION: Washoe County, Nevada; approximately 300 feet south and 1000 feet west of the northeast corner of section 8, T. 27 N., R. 19 E.; USGS Flanigan 7.5 minute topographic quadrangle; latitude 40 degrees 13 minutes 49 seconds N and longitude 119 degrees 51 minutes 57 seconds W; WGS84 Decimal Degrees 40.2303333 latitude, -119.865944 longitude.

RANGE IN CHARACTERISTICS:
Soil moisture: Usually moist in winter and spring, dry in summer and early autumn; aridic moisture regime that borders on xeric.
Mean annual soil temperature: 8 to 12 degrees C.
Ochric epipedon thickness: 3 to 13 cm.
Depth to base of argillic horizon: 18 to 36 cm.
Depth to bedrock: 18 to 36 cm to a lithic contact.
Reaction: Neutral or slightly alkaline.

Particle-size control section - Clay content: Averages 18 to 26 percent.
Rock fragments: 10 to 25 percent, mainly gravel. Lithology of fragments is volcanic rocks such as basalt.

A horizon
Hue: 10YR or 7.5YR.
Value: 5 or 6 dry, 3 or 4 moist.
Chroma: 2 or 3, dry or moist.

Bt1 horizon
Hue: 10YR or 7.5YR.
Value: 5 or 6 dry, 3 through 5 moist.
Chroma: 3 or 4, dry or moist; some pedons have 2 in the upper part.
Texture: Loam or gravelly loam.
Clay content: 18 to 26 percent.
Rock fragments: 10 to 25 percent.

Bt2 horizon
Hue: 10YR or 7.5YR.
Value: 5 or 6 dry, 4 or 5 moist.
Chroma: 3 or 4, dry or moist.
Texture: Loam, clay loam, gravelly loam, or gravelly clay loam.
Clay content: 25 to 35 percent.
Rock fragments: 10 to 20 percent.
Consistence: Very friable or friable, slightly sticky or moderately sticky, slightly plastic or moderately plastic.

COMPETING SERIES: These are the Banbury, Dougal, Fubble, Jaybee, Kreza, Meninick and Stumount series.

Banbury soils have 25 to 35 percent clay throughout the argillic horizon. Dougal soils have slightly acid soil reaction class in the argillic horizon. Fubble soils are 36 to 50 cm to lithic contacts. Jaybee soils have 35 to 45 percent clay in the argillic horizon. Kreza soils have 15 to 30 percent pararock fragments in the particle-size control section. Meninick soils have moderately acid or slightly acid soil reaction above the argillic horizon. Stumount soils have 25 to 35 percent rock fragments.

GEOGRAPHIC SETTING: Bombadil soils are on hills, plateaus, and mountains. They formed in colluvium and residuum derived from volcanic rocks. Slopes are 2 to 50 percent. Elevations range from 1,250 to 2,033 meters. The climate is semiarid with cool, moist winters and warm, dry summers. The mean annual precipitation is 200 to 300 mm, the mean annual temperature is 8 to 9 degrees C, and the frost-free period is 80 to 110 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Jaybee soil and the Old Camp, Reywat, and Skedaddle soils. Old Camp, Reywat, and Skedaddle soils are loamy-skeletal. Also, Reywat soils have mollic epipedons and Skedaddle soils do not have argillic horizons.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; very high surface runoff; moderately high saturated hydraulic conductivity.

USE AND VEGETATION: Bombadil soils are used for rangeland and wildlife habitat. The present vegetation is mainly Wyoming big sagebrush, bottlebrush squirreltail, and Thurber's needlegrass.

DISTRIBUTION AND EXTENT: Western Nevada and northeastern California. These soils are moderately extensive. The series concept and main acreage is in MLRA 23, while other acreage occurs in MLRAs 26 and 27.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California.

SERIES ESTABLISHED: Washoe County (South Part), Nevada, 1980.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from the soil surface to 5 cm (A horizon).
Argillic horizon - The zone from 5 to 25 cm (Bt1 and Bt2 horizons).
Lithic contact - The boundary at 25 cm to underlying hard bedrock (R layer).
Particle-size control section - The zone from the soil surface to 25 cm (A, Bt1, and Bt2 horizons).

ADDITIONAL DATA: User Pedon site ID: 2007NV031003.

National Cooperative Soil Survey
U.S.A.